The present invention relates to an adjustable differential case in an axle assembly and more particularly to an adjustment collar for selectively positioning a differential case and ring gear relative to a housing and pinion gear.
Axle assemblies of the prior art include a differential case mounted in the carrier of the axle assembly. A ring gear is often formed on an outer peripheral surface to interface with a pinion gear to drive the ring gear and provide power to the axles. Many ring gears are formed of a separate piece and are bolted to the differential case. In such a case, to account for assembly tolerances, shim packs may be disposed between the ring gear and the differential case to properly align the ring gear with the pinion gear once the differential assembly is installed in the carrier. Such prior art assemblies are costly, cumbersome, and required the differential case to be removed from the carrier and the ring gear detached from the differential case in order to adjust the portion of the ring gear. Often the prior art differential assemblies provide no significant means to adjust the position of the ring gear resulting in reduced performance and premature wear of the axle assembly.
The present invention is directed to an axle assembly with an adjustment mechanism to adjust the position of the ring gear relative to the housing and consequently the pinion gear. A pair of adjustment collars are provided on opposite sides of the differential case and disposed between the differential case and the housing. A pair of bearings are disposed between the adjustment collars and the housing to provide a rotatable connection between the differential case and the housing. The adjustment collars threadingly engage the differential case whereby rotation of the adjustment collar cause the differential case together with the ring gear to move along its axis of rotation. One of the adjustment collars is first rotated to position the differential case and the second adjustment collar is thereafter rotated to adjust the preload of the bearings. In an alternate embodiment a single adjustment collar is provided. A spacer of select thickness is disposed between one of the bearings and the housing and a select number of shims are disposed between the first bearing and the differential case to properly position the differential case and ring gear. Once the differential case and ring gear are properly positioned, the adjustment collar is rotated to adjust bearing preload. In both embodiments, once the differential case is positioned and bearing preload established, a locking member is employed to lock the adjustment collar in place.